Preparation of phosphorus compounds

ABSTRACT

The present invention relates to a process for preparing phosphorus compounds and intermediates.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a process for preparing phosphorus compounds and intermediates.

2. Brief Description of the Prior Art

Deblon (Thesis No. 13920, ETH Zurich, 2000) and Maire (Thesis No. 14396, ETH Zurich, 2001) disclose that transition metal complexes of olefin-phosphine compounds are particularly suitable for homogeneous catalytic reactions, especially hydrogenations and hydrosilylations. Typically, they are prepared by using secondary phosphines (see also Thomaier et al., New. J. Chem. 1998, 947-958 and Deblon et al., New. J. Chem. 2001, 25, 83-92), which is unsatisfactory for industrial use due to their spontaneous combustibility and associated safety requirements.

There is therefore a need to develop a process for preparing olefin-phosphine compounds which does not require the use of secondary phosphines.

SUMMARY OF THE INVENTION

Surprisingly, a process has now been found for preparing compounds of the formula (I)

in which

-   R¹ and R² are each independently a monovalent radical which in each     case has 1 to 30 carbon atoms or -   PR¹R² as a whole is a 5- to 9-membered heterocyclic radical which     contains a total of 2 to 50 carbon atoms and may contain up to three     further heteroatoms which are selected from the group of oxygen and     nitrogen, and -   A¹ and A² are each independently a substituted or unsubstituted     ortho-arylene radical and -   E is E¹ or E² where E¹ is an unsubstituted, monosubstituted or     disubstituted vicinal cis-alkenediyl radical and E² is a vicinal     alkanediyl radical in which the two yl carbon atoms each bear one or     two hydrogen atoms,     which is characterized in that     -   in a step a)         -   compounds of the formula (II)         -   in which A¹, A² and E are each as defined above are             converted by reacting with compounds of the formula (III)             R¹R²P-Hal  (III)         -   in which R¹ and R² are each as defined above and         -   Hal¹ is chlorine, bromine or iodine, preferably chlorine,         -   in the presence of acid or base,         -   to compounds of the formula (IV)         -   in which A¹, A², E, R¹ and R² are each as defined above and     -   in a step b), the compounds of the formula (IV) are converted to         compounds of the formula (I) by reduction.

The compounds of formulae (I) and (IV) also encompass in particular chiral compounds. These may occur in various stereoisomeric forms which behave either as image and mirror image (enantiomers) or do not behave as image and mirror image (diastereomers). The process according to the invention is suitable both for the preparation of stereoisomerically pure forms of the particular compound or any mixtures of the stereoisomers, for example racemates or diastereomer pairs.

In the context of the invention, the terms stereoisomerically enriched (enantiomerically enriched or diastereomerically enriched) mean stereoisomerically pure (enantiomerically pure or diastereomerically pure) compounds or mixtures of stereoisomers (enantiomers or diastereomers) in which one stereoisomer (enantiomer or diastereomer) is present in a greater fraction than another or the other. Stereoisomerically enriched means, for example and with preference, a content of one stereoisomer of 50% to 100% by weight, more preferably 70% to 100% by weight and most preferably 90 to 100% by weight, based on the sum of the stereoisomers.

In one embodiment of the process according to the invention, in the case of the presence of stereoisomer mixtures of compounds of the formula (IV), these may be separated in a manner known per se.

In the case of diastereomer mixtures, the separation may be effected, for example, by chromatography or by fractional crystallization, in the case of enantiomer mixtures, for example, by fractional crystallization in the presence of an enantiomerically enriched auxiliary reagent or by chromatography on an at least enantiomerically enriched column material.

In a further embodiment, the stability of the phosphorus-oxygen bond may also be used to convert at least one of the R¹, R², A¹, A² and E radicals in the compounds of the formula (IV) by chemical transformations known per se to another R¹, R², A¹, A² and E radical. Chemical transformations known per se are, for example, customary transformations of functional groups or functionalizations, as described in J. March, Advanced Organic Chemistry, Wiley, 1992.

In the context of the invention, all radical definitions, parameters and illustrations hereinabove and listed hereinbelow, mentioned generally or within areas of preference, i.e. the particular areas and areas of preference, may be combined as desired.

DETAILED DESCRIPTION OF THE INVENTION

In the context of the invention, aryl as a substituent is, for example, carbocyclic aromatic radicals having 6 to 24 skeleton carbon atoms, for example preferably phenyl, naphthyl, phenanthrenyl and anthracenyl, or heteroaromatic radicals having 5 to 24 skeleton carbon atoms in which no, one, two or three skeleton carbon atoms per cycle, but at least one skeleton carbon atom in the entire molecule, are substituted by heteroatoms which are selected from the group of nitrogen, sulphur and oxygen. They are, for example, preferably pyridinyl, oxazolyl, thiophenyl, benzofuranyl, benzothiophenyl, dibenzofuranyl, dibenzothiophenyl, furanyl, indolyl, pyridazinyl, pyrazinyl, imidazolyl, pyrimidinyl and quinolinyl. In the context of the invention, specifications such as C₅ in the case of aryl radicals relates to the sum of the carbon atoms and heteroatoms of the aromatic skeleton.

Moreover, the carbocyclic aromatic radicals or heteroaromatic radicals may be substituted by up to five identical or different substituents per cycle. For example and with preference, the substituents are selected from the group of bromine, fluorine, chlorine, nitro, cyano, free and protected formyl, free and protected hydroxyl, C₁-C₁₂-alkyl, C₁-C₁₂-haloalkyl, C₁-C₁₂-alkoxy, C₁-C₁₂-haloalkoxy, C₅-C₁₄-aryl, for example phenyl, C₆-C₁₅-arylalkyl, for example benzyl, di(C₁-C₁₂-alkyl)amino, (C₁-C₁₂-alkyl)amino, CO(C₁-C₁₂-alkyl), OCO(C₁-C₁₂-alkyl), NHCO(C₁-C₁₂-alkyl), N(C₁-C₆-alkyl)CO(C₁-C₁₂-alkyl), CO(C₅-C₁₄-aryl), OCO(C₅-C₁₄-aryl), NHCO(C₅-C₁₄-aryl), N(C₁-C₆-alkyl)CO(C₅-C₄-aryl), COO—(C₁-C₁₂-alkyl), COO—(C₅-C₁₄-aryl), CON(C₁-C₁₂-alkyl)₂ or CONH(C₁-C₁₂-alkyl), CO₂M, CONH₂, SO₂NH₂, SO₂N(C₁-C₁₂-alkyl)₂, SO₃M where M is in each case optionally substituted ammonium, lithium, sodium, potassium or caesium.

For example and with preference, aryl is phenyl, naphthyl, pyridinyl and quinolinyl, each of which may be further substituted by no, one, two or three radicals per cycle by radicals which are selected from the group of fluorine, chlorine, cyano, C₁-C₈-alkyl, C₁-C₆-perfluoroalkyl, C₁-C₆-alkoxy, phenyl, benzyl, di(C₁-C₁₂-alkyl)amino, CO(C₁-C₁₂-alkyl), COO—(C₁-C₁₂-alkyl), CON(C₁-C₁₂-alkyl)₂ and SO₂N(C₁-C₁₂-alkyl)₂.

More preferably, aryl is phenyl or naphthyl, each of which may be substituted by no, one, two or three radicals per cycle by radicals which are selected from the group of fluorine, chlorine, cyano, C₁-C₆-alkyl, C₁-C₆-perfluoroalkyl, C₁-C₈-alkoxy, phenyl and SO₂N(C₁-C₁₂-alkyl)₂.

In the context of the invention, the definition and the areas of preference also apply similarly to aryloxy substituents and the aryl moiety of an arylalkyl radical. Protected formyl means a formyl radical which is protected by conversion to an aminal, acetal or a mixed aminal acetal, and aminals, acetals and mixed aminal acetals may be acyclic or cyclic.

For example and with preference, protected formyl is a 1,1-(2,4-dioxycyclopentanediyl) radical.

Protected hydroxy is a hydroxyl radical which is protected by conversion to a ketal, acetal or a mixed aminal acetal, and the acetals and mixed aminal acetals may be acyclic or cyclic.

For example and with preference, protected hydroxyl is a tetrahydropyranyl radical (THP).

In the context of the invention, alkyl, alkylene, alkoxy and alkenyl are in each case independently a straight-chain, cyclic, branched or unbranched alkyl, alkylene, alkenyl and alkoxy radical respectively, each of which may be further substituted by C₁-C₄-alkoxy in such a way that each carbon atom of the alkyl, alkylene, alkoxy or alkenyl radical bears at most one heteroatom selected from the group of oxygen, nitrogen and sulphur.

The same applies to the alkylene moiety of an arylalkyl radical.

In the context of the invention, C₁-C₆-alkyl is, for example, methyl, ethyl, 2-ethoxyethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl, cyclohexyl and n-hexyl, C₁-C₈-alkyl is additionally, for example, n-heptyl, n-octyl or isooctyl, C₁-C₁₂-alkyl is further additionally, for example, norbornyl, adamantyl, n-decyl and n-dodecyl, and C₁-C₁₈-alkyl is still further additionally n-hexadecyl and n-octadecyl.

In the context of the invention, C₁-C₄-alkylene is, for example, methylene, 1,1-ethylene, 1,2-ethylene, 1,1-propylene, 1,2-propylene, 1,3-propylene, 1,1-butylene, 1,2-butylene, 2,3-butylene and 1,4-butylene, and C₁-C₈-alkylene is additionally 1,5-pentylene, 1,6-hexylene, 1,1-cyclohexylene, 1,4-cyclohexylene, 1,2-cyclohexylene and 1,8-octylene.

In the context of the invention, C₁-C₄-alkoxy is, for example, methoxy, ethoxy, isopropoxy, n-propoxy, n-butoxy and tert-butoxy, and C₁-C₈-alkoxy is additionally cyclohexyloxy.

In the context of the invention, C₂-C₈-alkenyl is, for example, allyl, 3-propenyl and 4-butenyl.

Haloalkyl and haloalkoxy are in each case independently a straight-chain, cyclic, branched or unbranched alkyl and alkoxy radical respectively, each of which is singly, multiply or fully substituted by halogen atoms. Radicals which are fully substituted by fluorine are referred to as perfluoroalkyl and perfluoroalkoxy respectively.

In the context of the invention, C₁-C₆-haloalkyl is, for example, trifluoromethyl, 2,2,2-trifluoroethyl, chloromethyl, fluoromethyl, bromomethyl, 2-bromoethyl, 2-chloroethyl, nonafluorobutyl. C₁-C₈-haloalkyl is additionally, for example, n-perfluorooctyl, and C₁-C₁₂-haloalkyl is additionally, for example, n-perfluorododecyl.

In the context of the invention, C₁-C₄-haloalkoxy is, for example, trifluoromethoxy, 2,2,2-trifluoroethoxy, 2-chloroethoxy, heptafluoroisopropoxy, and C₁-C₈-haloalkoxy is additionally n-perfluorooctyloxy.

The preferred substitution patterns are defined hereinbelow:

-   R¹ and R² are preferably each independently C₁-C₁₈-alkyl,     C₃-C₁₂-alkenyl, C₁-C₁₈-perfluoroalkyl, C₁-C₁₈-perfluoroalkoxy,     C₁-C₁₈-alkoxy, C₅-C₂₄-aryl, C₅-C₂₄-aryloxy, C₅-C₂₅-arylalkyl,     C₅-C₂₅-arylalkoxy or NR⁴R⁵ where R⁴ and R⁵ are each independently     C₁-C₁₂-alkyl, C₅-C₁₄-aryl or C₆-C₁₅-arylalkyl, or NR⁴R⁵ as a whole     is a 5- to 7-membered cyclic amino radical having a total of 4 to 12     carbon atoms, or -   PR¹R² as a whole is a 5- to 7-membered heterocyclic radical of the     formula (V)     in which -   Het¹ and Het² are each independently absent, or are each oxygen or     NR⁵ where R⁵ is C₁-C₁₂-alkyl, C₅-C₁₄-aryl or C₆-C₁₅-arylalkyl and -   K is an alkanediyl radical having 2 to 25 carbon atoms, a divalent     arylalkyl radical having 5 to 15 carbon atoms, an arylene radical     having a total of 5 to 14 carbon atoms or a 2,2′-(1,1′-bisarylene)     radical having a total of 10 to 30 carbon atoms. -   R¹ and R² are more preferably each independently C₁-C₁₂-alkyl,     C₅-C₁₄-aryl, C₆-C₂₅-arylalkyl or radicals of the formula (V) in     which Het¹ and Het² are each identically absent or are each     independently oxygen or nitrogen and -   K is a C₁-C₈-alkylene radical or a 2,2′-(1,1′-bisphenylene) or     2,2′-(1,1′-bisnaphthylene) radical which are further substituted by     up to two substituents per cycle selected from the group of     fluorine, chlorine, C₁-C₄-alkyl and C₁-C₄-alkoxy. -   R¹ and R² are even more preferably each independently and, still     more preferably, each identically, methyl, ethyl, n-propyl,     isopropyl, tert-butyl, cyclohexyl, benzyl, o-, m-, p-tolyl,     2,6-dimethylphenyl, 3,5-di-tert-butylphenyl,     p-trifluoromethylphenyl, 3,5-bis(trifluoromethylphenyl),     p-tert-butylphenyl, o-, m-, p-anisyl, 2,6-dimethoxyphenyl, o-, m-,     p-dimethylaminophenyl, 2-, 3-, 4-pyridyl, 2-furanyl, 2-pyrrolyl or     radicals of (IV) in which either     -   Het¹ and Het² are each absent and     -   K is a C₁-C₈-alkylene radical or     -   Het¹-K-Het² as a whole is a 2,2-dioxy-(1,1-binaphthyl) radical         or a 2,2′-dioxy-(1,1′-biphenyl) radical which is disubstituted         at least in the 6,6′-positions, but has at most two substituents         per cycle, and the substituents are selected from the group of         fluorine, chlorine, C₁-C₄-alkyl and C₁-C₄-alkoxy. -   PR¹R² is most preferably as a whole diisopropylphosphino,     di-tert-butylphosphino, dicyclohexylphosphino, diphenylphosphino,     bis(o-, m-, p-tolyl)phosphino,     di-(3,5-bis(trifluoromethylphenyl)phosphino, di-(o-anisyl)phosphino,     di-(2-pyridyl)phosphino, (R,R)-2,5-dimethylphospholano, or     (S,S)-2,5-dimethylphospholano. -   A¹ and A² are preferably each independently an ortho-phenylene     radical of the formula (VI)     in which -   n is 0, 1, 2, 3 or 4, preferably 0, 1 or 2, and more preferably 0 or     1, and -   R⁶ is in each case independently selected from the group of     fluorine, chlorine, bromine, iodine, nitro, free and protected     formyl, C₁-C₁₂-alkyl, C₁-C₁₂-alkoxy, C₁-C₁₂-haloalkoxy,     C₁-C₁₂-haloalkyl, C₅-C₁₄-aryl, C₆-C₁₅-arylalkyl or radicals of the     formula (VI)     L-Q-T-W  (VII)     -   in which, each independently,     -   L is absent or is C₁-C₈-alkylene or C₂-C₈-alkenylene and     -   Q is absent or is oxygen, sulphur or NR⁷         -   where         -   R⁷ is hydrogen, C₁-C₈-alkyl, C₆-C₁₅-arylalkyl or C₅-C₁₄-aryl             and     -   T is a carbonyl group and     -   W is R⁸, OR⁸, NHR⁹ or N(R⁹)₂,         -   where         -   R⁸ is C₁-C₈-alkyl, C₅-C₁₅-arylalkyl or C₅-C₁₄-aryl and         -   R⁹ is in each case independently C₁-C₈-alkyl,             C₅-C₁₄-arylalkyl or C₄-C₁₅-aryl, or N(R⁹)₂ together is a 5-             or 6-membered cyclic amino radical,             or a radical of the formulae (VIIIa-g)             L-W  (VIIIa)             L-SO₂—W  (VIIIb)             L-NR¹²SO₂R¹²  (VIIIc)             L-SO₃Z  (VIIId)             L-PO₃Z₂  (VIIIe)             L-COZ  (VIIIf)             L-CN  (VIIIg)             in which L, Q, W and R⁸ are each as defined under the             formula (VII) and Z is hydrogen or M¹ where M¹ is as defined             under the definition of R⁷.

A¹ and A² are more preferably each independently, even more preferably identically, an ortho-phenylene radical of the formula (VI) in which

-   n is 0 or 1 and -   R⁶ is in each case independently selected from the group of     -   fluorine, chlorine, bromine, iodine, cyano, C₁-C₄-alkyl,         C₁-C₄-alkoxy, di-(C₁-C₄-alkyl)amino, (C₁-C₄-alkyl)amino,         C₁-C₄-alkylthio, CO₂M¹, CONH₂, SONH₂, SO₂N(C₁-C₄-alkyl)₂, SO₃M¹         where M¹ is in each case lithium, sodium or potassium.

A¹ and A² are still more preferably identically an ortho-phenylene radical of the formula (VI) in which

-   n is 0 or 1 and -   R⁶ is selected from the group of fluorine, chlorine, cyano, methyl,     ethyl, methoxy, ethoxy, methylthio, dimethylamino, CONH₂,     SO₂N(methyl)₂ or SO₂N(ethyl)₂ where, when n=1, R⁶ is still more     preferably arranged in the para-position to E.

A¹ and A² are most preferably each identically ortho-phenylene.

-   E¹ is preferably a radical of the formula (IXa)     in which -   R¹⁰ and R¹¹ are each independently hydrogen, cyano, fluorine,     chlorine, bromine, iodine, C₁-C₁₈-alkyl, C₄-C₂₄-aryl,     C₅-C₂₅-arylalkyl, CO₂M, CONH₂,

SO₂N(R¹²)₂, SO₃M¹, where R¹² is in each case independently as defined above or is a radical of the formula (X), T²-Het³-R¹³  (X)

-   -   in which     -   T² is absent or is carbonyl,     -   Het³ is oxygen or NR¹² where R¹² is hydrogen, C₁-C₁₂-alkyl,         C₅-C₁₄-aryl or C₆-C₁₅-arylalkyl and     -   R¹³ is C₁-C₁₈-alkyl, C₅-C₂₄-aryl or C₅-C₂₅-arylalkyl.

-   E² is preferably a radical of the formula (IXb)     in which

-   R¹⁴ and R¹⁵ are each independently hydrogen, C₁-C₁₈-alkyl,     C₅-C₂₄-aryl or C₅-C₂₅-arylalkyl.

-   E is preferably E¹.

E¹ is more preferably a radical of the formula (IXa) in which one of the two R¹⁰ and R¹¹ radicals is hydrogen and the other radical is selected from the group of hydrogen, cyano, fluorine, C₁-C₁₂-alkyl, phenyl, C₁-C₁₈-alkoxy and C₅-C₁₅-arylalkoxy, where C₁-C₁₈-alkoxy and C₅-C₁₅-arylalkoxy are preferably chiral.

Very particular preference is given to one of the two R¹⁰ and R¹¹ radicals being hydrogen and the other radical being selected from the group of hydrogen, cyano, fluorine, phenyl, methoxy and menthoxy, (−)-menthoxy being preferred among the 8 isomers.

The process according to the invention is especially suitable for preparing the following compounds:

-   10-cyano-5-diphenylphosphinyl-5H-dibenzo[a,d]cycloheptene     (^(CN)tropp^(Ph)), -   5-(2S,5S-2,5-dimethylphospholanyl)-5H-dibenzo[a,d]cycloheptene     (S,S-tropphos^(Me)), -   5-(2R,5R-2,5-dimethylphospholanyl)-5H-dibenzo[a,d]cycloheptene     (R,R-tropphos^(Me)), -   (10-methoxy-5H-dibenzo[a,d]cyclohepten-5-yl)diphenylphosphine     (^(MeO)tropp^(Ph)), -   (10-methoxy-5H-dibenzo[a,d]cyclohepten-5-yl)dicyclohexylphosphine     (^(MeO)tropp^(Cyc)), -   [(5S)-10-[(−)-menthyloxy]-5H-dibenzo[a,d]cyclohepten-5-yl]diphenylphosphine,     (S-^(menthyloxy)tropp^(Ph)) and     [(5R)-10-[(−)-menthyloxy]-5H-dibenzo[a,d]cyclohepten-5-yl]diphenylphosphine     (R-^(menthyloxy)tropp^(Ph)) are prepared.

In step a) of the process according to the invention, the compounds of the formula (II) are reacted with compounds of the formula (III) in the presence of acid or base to give compounds of the formula (IV).

The reaction may optionally and preferably be carried out in the presence of organic solvent, as long as the solvents are at least substantially inert towards the particular acid or base used.

Suitable organic solvents are, for example:

aliphatic or aromatic, optionally halogenated hydrocarbons, for example various benzines, benzene, toluene, xylene, chlorobenzene, dichlorobenzene, various petroleum ethers, hexane, cyclohexane, dichloromethane, chloroform, carbon tetrachloride; ethers such as diethyl ether, methyl tert-butyl ether, diisopropyl ether, dioxane, tetrahydrofluan or ethylene glycol dimethyl ether or ethylene glycol diethyl ether; amides such as N,N-dimethylformamide, N,N-dimethyl-acetamide, N-methylformanilide, N-methylpyrrolidone, N-methylcaprolactam or hexamethylphosphoramide; sulphoxides such as dimethyl sulphoxide, sulphones such as tetramethylenesulphone, alcohols such as methanol, ethanol, n- or isopropanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, or mixtures of such organic solvents. Preferred organic solvents are ethers.

Suitable bases are, for example: alkaline earth metal or alkali metal hydrides, hydroxides, amides, alkoxides or carbonates, for example sodium hydride, sodium amide, lithium diethylamide, sodium methoxide, sodium ethoxide, potassium tert-butoxide, sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate, organolithium compounds, for example n-butyllithium or methyllithium, tertiary amines such as trimethylamine, triethylamine, tributylamine, trioctylamine, diisopropylethylamine, tetramethylguanidine, N,N-dimethylaniline, diazabicyclooctane (DABCO), diazabicyclononene (DBN) or diazabicycloundecene (DBU), piperidine and N-methylpiperidine and N-heteroaromatics, for example pyridine and N,N-dimethylaminopyridine.

Preferred bases are tertiary amines in which the radicals are each independently selected from the group of C₁-C₁₂-alkyl, for example trimethylamine, triethylamine, tributylamine and trioctylamine, and even greater preference is given to those tertiary amines which are liquid under the selected reaction conditions.

Preference is given to using acids for the process according to the invention.

Preferred acids are those which, based on an aqueous reference scale and 25° C., have a pKa value of 5.5 or less.

These are, for example, (C₁-C₁₂-alkyl)carboxylic acids, (C₁-C₁₂-haloalkyl)carboxylic acids, (C₁-C₁₂-haloalkyl)sulphonic acids, (C₁-C₁₂-alkyl)sulphonic acids, (C₅-C₁₄-aryl)sulphonic acids, hydrogen chloride, hydrogen bromide and hydrogen iodide, optionally dissolved in acetic acid, sulphuric acid, ortho- and polyphosphoric acids, hexafluorophosphoric acid and tetrafluoroboric acid.

Particular preference is given to (C₁-C₁₂-haloalkyl)carboxylic acids, in particular trifluoroacetic acid.

The reaction in step a) may be carried out, for example, at a temperature of −20° C. to 100° C., preferably at 0 to 80° C. and more preferably at ambient temperature.

The reaction pressure may be, for example, 0.5 to 100 bar, preferably 0.9 to 5 bar. Particular preference is given to ambient temperature.

For example and with preference, acid and compound of the formula (II) may be initially charged in an organic solvent and the compound of the formula (III) added.

In step b) of the process according to the invention, compounds of the formula (IV) are reduced.

Preference is given to effecting this reduction in the presence of hydrosilicon compounds. Preferred hydrosilicon compounds are polymethylhydrosiloxane (PHMS) or those of the formula (XI) (R¹⁶)_(p)SiH_(4-p)  (XI) in which

-   p is 0, 1, 2 or 3 and -   R¹⁶ is in each case independently C₁-C₈-alkyl, C₁-C₈-alkoxy,     C₅-C₁₄-aryl or chlorine, and even greater preference is given to     trichlorosilane.

Preference is given to carrying out the reaction in the presence of solvent.

Preferred solvents are aliphatic or aromatic, optionally halogenated hydrocarbons, for example various benzines, benzene, toluene, xylene, chlorobenzene, dichlorobenzene, various petroleum ethers, hexane, cyclohexane, dichloromethane, chloroform, carbon tetrachloride or mixtures thereof.

The reaction in step b) may be carried out, for example, at a temperature of 20° C. to 200° C., preferably 50 to 150° C. and more preferably at 100 to 150° C.

The reaction pressure may be, for example, 0.5 to 100 bar, preferably 0.9 to 5 bar. Particular preference is given to ambient pressure.

For example and with preference, the hydrosilicon compound and the compound of the formula (IV) may be initially charged at room temperature in an organic solvent and the reaction mixture then heated at ambient pressure to the boiling point of the solvent used.

In a further aspect, the invention relates to compounds of the formula (IVa) and also to a process for preparing compounds of the formula (IVa)

in which A¹, A² and E are each as defined under the formula (I) including their areas of preference and

-   Hal is in each case independently chlorine, bromine or iodine,     preferably identically chlorine or bromine and more preferably     identically chlorine,     which is characterized in that compounds of the formula (II) as     defined above are reacted in the presence of acid or base with     compounds of the formula (IIIa)     PHal₃  (IIIa)     in which -   Hal is in each case independently chlorine, bromine or iodine,     preferably identically chlorine or bromine and more preferably     identically chlorine.

All specifications made above for step a) apply here correspondingly.

Compounds of the formula (IVa) include:

-   5-dichlorooxyphosphoryl-5H-dibenzo[a,d]cycloheptene (troppo^(Cl))     and 5-dibromooxyphosphoryl-5H-dibenzo[a,d]cycloheptene (troppo^(Br))

The compounds of the formula (IVa) are valuable intermediates and can be prepared, for example, by reacting with compounds of the formula (XII) R^(1/2)-M  (XII) in which R¹ and R² are each as defined above including the areas of preference specified and M, in the case that

-   R¹ or R² are to be bonded to the phosphorus atom via an oxygen atom,     is hydrogen or 1/n equivalent of a metal or of a metal fragment     having the valency n, and, in the case that -   R¹ or R² are to be bonded to the phosphorus atom via a nitrogen     atom, is hydrogen, and, in the case that -   R¹ or R² are to be bonded to the phosphorus atom via a carbon atom,     is 1/n equivalent of a metal or of a metal fragment having the     valency n, the same also applying in a similar manner to radicals in     which R¹R² as a whole is a divalent radical.

Preferred metals are alkali metal, alkaline earth metal or transition metals, for example lithium, potassium, sodium, magnesium, zinc or copper, and particular preference is given to lithium, magnesium and zinc:

Preferred metal fragments are monovalent halometal fragments, for example MgCl, MgBr, MgI, ZnCl, ZnBr and ZnI.

The compounds obtainable in this way which can be encompassed by the formula (IV) may then likewise be reduced in step b) to the free phosphines of the formula (I).

The compounds of the formula (I) which can be prepared in accordance with the invention are especially suitable as ligands for metals and for use in catalytic processes. Preferred catalytic processes are hydrogenations and hydrosilylations.

The compounds of the formula (IV) and (IVa) which can be prepared in accordance with the invention are especially suitable for use in a process for preparing ligands and catalysts.

The advantage of the present invention is that, using compounds which are easy to obtain and can be handled without risk, olefin-phosphorus compounds can be prepared in high yields.

The invention is further illustrated but is not intended to be limited by the following examples in which all parts and percentages are by weight unless otherwise specified.

EXAMPLES Example 1 Synthesis of 5-diphenyloxophosphoranyldibenzo[a,d]cycloheptene (troppo^(ph))

In a 500 ml reaction vessel, 14 g of dibenzo[a,d]cyclohepten-5-ol (0.067 mol) are dissolved in 250 ml of THF. Subsequently, 11.1 ml of trifluoroacetic acid (0.144 mol) are added and subsequently 25.84 ml of dichlorophenylphosphine (0.144 mol) are added. A white precipitate forms. The reaction mixture is left to stir at room temperature for 30 minutes. Subsequently, the reaction mixture is neutralized using K₂CO₃ solution. The organic phase is removed, and the residues are washed three times with 100 ml of [lacuna] and once with 100 ml of Et₂O. The combined organic phases are dried over Na₂SO₄ and the solvent is subsequently removed. The residue is recrystallized from CH₂Cl₂/n-hexane and 18.38 g (70% yield) of a colourless crystalline solid are obtained.

³¹P NMR (CDCl₃, 121 MHz): δ 29.28

¹H NMR (CDCl₃, 300 MHz): δ 4.93 [d, ²J(PH)=16 Hz, 1H, PCH_(benzyl)), 6.56 (s, 2H, H_(olefin)), 7.59-7.17 (m, 19H, H_(arom)).

Example 2 Synthesis of 5-diphenylphosphinyldibenzo[a,d]cycloheptene (tropp^(ph))

In a 100 ml reaction vessel with reflux condenser, 1 g of troppo^(Ph) from Example 1 (2.7 mmol) is dissolved in 50 ml of toluene and admixed with 2.6 ml of HSiCl₃. The reaction mixture is heated to 120° C. for 8 h. The progress of the reaction is monitored by ³¹P NMR spectroscopy. The reaction mixture is cooled to 0° C. and 30 ml of a deoxygenated 20% NaOH solution are added dropwise. Subsequently, the organic phase is separated and dried over Na₂SO₄. After the solvent has been evaporated off under reduced pressure, 0.88 g (93% yield) of pure tropp^(Ph) is obtained.

³¹P NMR (CDCl₃, 101 MHz): δ −14.2 (s).

¹H NMR (CDCl₃, 250 MHz): δ 4.93 (d, ²J(PH)=5.5 Hz, 2H, PCH_(benzyl)), 7.20-6.87 (m, 15H, H_(arom)), 7.25 (s, 2H, H_(olefin)), 7.44-7.41 (m, 3H, H_(arom)).

Example 3 Synthesis of 5-diphenyloxophosphoranyl-10-phenyldibenzo[a,d]cycloheptene (^(ph)troppo^(ph))

520 mg of 5-hydroxy-10-phenyldibenzo[a,d]cycloheptene (1.8 mmol) in 15 ml of CH₂Cl₂ are admixed with 0.15 ml of CF₃COOH (1.13 mmol). The solution becomes red and 0.33 ml of chlorodiphenylphosphine (2.26 mmol) is added. Another 0.15 ml of CF₃COOH (1.13 mmol) is then added to the reaction mixture. This gives a clear yellow solution which is stirred at room temperature for 2 h. Subsequently, 20 ml of Na₂CO₃ (18% in H₂O) are added. The organic phase is removed and the aqueous extracted 3× with 20 ml of CH₂Cl₂ each time. The combined organic phases are dried over MgSO₄ and the solvent is subsequently evaporated. This gives a white foam which contains spectroscopically pure product (660 mg, 80%).

³¹P NMR: 27.3 ppm—¹H NMR: 5.15 (d, ²JPH=13 Hz, 1H, CHP), 6.50 (s, 1H. ═CH), 7.0-7.9 (m, 23H, H_(arom)).

Example 4 Synthesis of 5-diphenylphosphinyl-10-phenyldibenzo[a,d]cycloheptene (^(ph)tropp^(ph))

660 mg of 5-diphenyloxophosphoranyl-10-phenyldibenzo[a,d]cycloheptene (1.44 mmol) are dissolved in 20 ml of toluene and 1.8 ml of SiHCl₃ are added. The reaction mixture is heated to 120° C. under reflux for 10 h. After cooling, 25 ml of 20% deoxygenated KOH are added with cooling. The organic phase is removed and dried over MgSO₄. After removing all volatile components, a yellow foam is obtained which fluoresces intensely under UV light.

³¹P NMR (CDCl₃): −13.1 ppm—¹H NMR: 4.99 (d, ²J_(PH)=6 Hz, 1H. CHP), 6.90 (d, J_(PH)=6 Hz, 1H, ═CH), 7.0-7.53 (m, 23H, Harom).

Example 5 Synthesis of 5-diallyloxophosphoranyldibenzo[a,d]cycloheptene (troppo^(allyl))

To a solution of 50 mg of 5-dichlorooxophosphoranyldibenzo[a,d]cycloheptene, which has been prepared in a similar manner to Example 1 (0.2 mmol) in 1 ml of THF is added 0.2 ml of allylmagnesium chloride (2 M in THF). The reaction mixture becomes red-brown. After 1 h at room temperature, the reaction mixture is admixed with aqueous ammonium chloride solution and the organic phase is removed. The aqueous phase is extracted with CH₂Cl₂ and the combined organic phases are dried over MgSO₄. After removing the solvent, 5-diallyloxophosphoranyldibenzo[a,d]cycloheptene is obtained as a colourless solid.

³¹P NMR (CDCl₃): 45.8 ppm—¹H NMR: 2.44 (dd, ²J_(PH)=14.5 Hz, ³J_(HH)=7.6 Hz, 2H, CH₂), 4.49 (d, ²J_(PH)=16.2 Hz, 1H, CHP).

Example 6 Synthesis of 5-diallylphosphinyldibenzo[a,d]cycloheptene (tropp^(allyl))

In a similar manner to Example 4, 5-diallyloxophosphoranyldibenzo[a,d]cycloheptene is reduced quantitatively using HSiCl₃ in toluene within 2 h to 5-diallylphosphinyldibenzo[a,d]cycloheptene.

³¹p NMR (CDCl₃): −28.1 ppm.

Although the invention has been described in detail in the foregoing for the purpose of illustration, it is to be understood that such detail is solely for that purpose and that variations can be made therein by those skilled in the art without departing from the spirit and scope of the invention except as it may be limited by the claims 

1. Process for preparing compounds of the formula (I)

in which R¹ and R² are each independently a monovalent radical which in each case has 1 to 30 carbon atoms or PR¹R² as a whole is a 5- to 9-membered heterocyclic radical which contains a total of 2 to 50 carbon atoms and optionally contains up to three further heteroatoms which are selected from the group of oxygen and nitrogen, and A¹ and A² are each independently a substituted or unsubstituted ortho-arylene radical and E is E¹ or E² where E¹ is an unsubstituted, monosubstituted or disubstituted vicinal cis-alkenediyl radical and E² is a vicinal alkanediyl radical in which the two yl carbon atoms each bear one or two hydrogen atoms, comprising in a step a), reacting compounds of the formula (II)

in which A¹, A² and E are each as defined above with compounds of the formula (III) R¹R²P-Hal  (III) in which R¹ and R² are each as defined above and Hal¹ is chlorine, bromine or iodine, in the presence of acid or base, to form compounds of the formula (IV)

in which A¹, A², E, R¹ and R² are each as defined above and in a step b), reducing the compounds of the formula (IV) to compounds of the formula (I).
 2. Process according to claim 1, characterized in that R¹ and R² are each independently C₁-C₁₈-alkyl, C₃-C₁₂-alkenyl, C₁-C₁₈-perfluoroalkyl, C₁-C₁₈-perfluoroalkoxy, C₁-C₁₈-alkoxy, C₅-C₂₄-aryl, C₅-C₂₄-aryloxy, C₅-C₂₅-arylalkyl, C₅-C₂₅-arylalkoxy or NR⁴R⁵ where R⁴ and R⁵ are each independently C₁-C₁₂-alkyl, C₅-C₁₄-aryl or C₆-C₁₅-arylalkyl, or NR⁴R⁵ as a whole is a 5- to 7-membered cyclic amino radical having a total of 4 to 12 carbon atoms, or PR¹R² as a whole is a 5- to 7-membered heterocyclic radical of the formula (V)

in which Het¹ and Het² are each independently absent, or are each oxygen or NR⁵ where R⁵ is C₁-C₁₂-alkyl, C₅-C₁₄-aryl or C₆-C₁₅-arylalkyl and K is an alkanediyl radical having 2 to 25 carbon atoms, a divalent arylalkyl radical having 5 to 15 carbon atoms, an arylene radical having a total of 5 to 14 carbon atoms or a 2,2′-(1,1′-bisarylene) radical having a total of 10 to 30 carbon atoms.
 3. Process according to claim 1, characterized in that A¹ and A² are each independently an ortho-phenylene radical of the formula (VI)

in which n is 0, 1, 2, 3 or 4, preferably 0, 1 or 2, and R⁶ is in each case independently selected from the group of fluorine, chlorine, bromine, iodine, nitro, free and protected formyl, C₁-C₁₂-alkyl, C₁-C₁₂-alkoxy, C₁-C₁₂-haloalkoxy, C₁-C₁₂-haloalkyl, C₅-C₁₄-aryl, C₆-C₁₅-arylalkyl or radicals of the formula (VII) L-Q-T-W  (VII) in which, each independently, L is absent or is C₁-C₈-alkylene or C₂-C₈-alkenylene and Q is absent or is oxygen, sulphur or NR⁷ where R⁷ is hydrogen, C₁-C₈-alkyl, C₆-C₁₅-arylalkyl or C₅-C₁₄-aryl and T is a carbonyl-group and W is R⁸, OR⁸, NHR⁹ or N(R⁹)₂, where R⁸ is C₁-C₈-alkyl, C₅-C₁₅-arylalkyl or C₅-C₁₄-aryl and R⁹ is in each case independently C₁-C₈-allyl, C₅-C₁₄-arylalkyl or C₄-C₁₅-aryl, or N(R⁹)₂ together is a 5- or 6-membered cycloamino radical, or a radical of the formulae (VIIIa-g) L-W  (VIIIa) L-SO₂—W  (VIIIb) L-NR¹²SO₂R¹²  (VIIIc) L-SO₃Z  (VIIId) L-PO₃Z₂  (VIIIe) L-COZ  (VIIIf) L-CN  (VIIIg) in which L, Q, W and R⁸ are each as defined under the formula (VII) and Z is hydrogen or M¹ where M¹ is as defined under the definition of R⁷.
 4. Process according to claim 1, characterized in that E is a radical of the formulae (IXa) or (IXb) where, in formula (IXa)

R¹⁰ and R¹¹ are each independently hydrogen, cyano, fluorine, chlorine, bromine, iodine, C₁-C₁₈-alkyl, C₄-C₂₄-aryl, C₅-C₂₅-arylalkyl, CO₂M, CONH₂, SO₂N(R¹²)₂, SO₃M¹, where R¹² is in each case independently as defined above or is a radical of the formula (X), T²-Het³-R¹³  (X) in which T² is absent or is carbonyl, Het³ is oxygen or NR¹² where R¹² is hydrogen, C₁-C₁₂-alkyl, C₅-C₁₄-aryl or C₆-C₁₅-arylalkyl and R¹³ is C₁-C₁₈-alkyl, C₅-C₂₄-aryl or C₅-C₂₅-arylalkyl, and, in formula (IXb),

R¹⁴ and R¹⁵ are each independently hydrogen, C₁-C₁₈-alkyl, C₅-C₂₄-aryl or C₅-C₂₅-arylalkyl.
 5. Process according to at least one of claims 1 to 4, characterized in that 10-cyano-5-diphenylphosphinyl-5H-dibenzo[a,d]cycloheptene (^(CN)tropp^(Ph)) 5-(2S,5S-2,5-dimethylphospholanyl)-5H-dibenzo[a,d]cycloheptene (S,S-tropphos^(Me)) 5-(2R,5R-2,5-dimethylphospholanyl)-5H-dibenzo[a,d]cycloheptene (R,R-tropphos^(Me)) (10-methoxy-5H-dibenzo[a,d]cyclohepten-5-yl)diphenylphosphine (^(MeO)tropp^(Ph)) (10-methoxy-5H-dibenzo[a,d]cyclohepten-5-yl)dicyclohexylphosphine (^(MeO)tropp^(Cyc)) [(5S)-10-[(−)-menthyloxy]-5H-dibenzo[a,d]cyclohepten-5-yl]diphenylphosphine, (S-^(menthyloxy)tropp^(Ph)) and [(5R)-10-[(−)-menthyloxy]-5H-dibenzo[a,d]cyclohepten-5-yl]-diphenylphosphine (R-^(menthyloxy)tropp^(Ph)) are prepared.
 6. Process according to claim 1, characterized in that acids are used for step a).
 7. Process according to claim 1, characterized in that the acids used are those which, based on an aqueous reference scale and 25° C., have a pKa value of 5.5 or less.
 8. Process according to claim 1, characterized in that step a) is carried out at a temperature of −20° C. to 100° C.
 9. Process according to claim 1, characterized in that stereoisomer mixtures of compounds of the formula (IV), are separated before carrying out step b).
 10. Process according to at least one of claims 1 to 9, characterized in that at least one of the R¹, R², A¹, A² and E radicals in the compounds of the formula (IV) is converted to another R¹, R², A¹, A² and E radical.
 11. Process according to claim 1, characterized in that the reduction in step b) is carried out in the presence of hydrosilicon compounds.
 12. Process according to claim 1, characterized in that the reduction in step b) is carried out at a temperature of 20° C. to 200° C.
 13. Process according to claim 1, characterized in that the resulting compounds are reduced to the free phosphines in a further step.
 14. Compounds of the formula (IVa)

in which A¹, A² and E are each as defined in claim
 1. 15. 5-Dichlorooxyphosphoryl-5H-dibenzo[a,d]cycloheptene (troppo^(Cl)) and 5-dibromooxyphosphoryl-5H-dibenzo[a,d]cycloheptene (troppo^(Br)).
 16. Process for preparing compounds of the formula (IVa)

in which A¹, A² and E are each as defined in claim 1 and Hal is in each case chlorine, bromine or iodine, comprising reacting compounds of the formula (II) as defined in claim 1 in the presence of acid or base with compounds of the formula (IIIa) PHal₃  (IIIa) in which Hal is in each case independently chlorine, bromine or iodine.
 17. Process according to claim 16, characterized in that the compounds of the formula (IVa) are also reacted with compounds of the formula (XII) R^(1/2)-M  (XII) in which R¹ and R² are each as defined in claim 1, and M, in the case that R¹ or R² are to be bonded to the phosphorus atom via an oxygen atom, is hydrogen or 1/n equivalent of a metal or of a metal fragment having the valency n, and, in the case that R¹ or R² are to be bonded to the phosphorus atom via a nitrogen atom, is hydrogen, and, in the case that R¹ or R² are to be bonded to the phosphorus atom via a carbon atom, is 1/n equivalent of a metal or of a metal fragment having the valency n, the same also applying in a similar manner to radicals in which R¹R² as a whole is a divalent radical.
 18. Process according to claim 17, characterized in that the resulting compounds are reduced to the free phosphines in a further step.
 19. A process for preparing ligand for metals or conducting catalytic processes comprising providing the compounds of claim
 14. 20. The process of claim 19, characterized in that the catalytic processes are hydrogenations and hydrosilylations. 